Chapter 9 Quadratic Relations and Conic Sections - 9.4 Graph and Write Equations of Ellipses - 9.4 Exercises - Problem Solving - Page 639: 52b

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The distance between airport $A$ and airport $B$ is 450 miles. Let $(0, 0)$ represent the center of the ellipse. The foci are at $(-c,0)$ and $(c,0)$ The focal distance is $c=\frac{450}{2}=225$ The coordinates of each airport are $(-225,0)$ and $(225,0)$.